Rotary closed loop drilling system designed for the next millennium

Far-reaching advancements in drilling technology have occurred in the oil and gas industry during the past 10 years. While the emphasis has mainly been on enhancing existing tools and techniques to improve rate of penetration (ROP), novel applications have also emerged, such as directional and horizontal drilling and formation evaluation measurement while drilling (FEMWD). In 1993, the feasibility of a complete new drilling system that would combine the best features of rotary drilling assemblies with those of steerable directional drilling assemblies was studied to meet the needs of future drilling applications. By combining these two drilling technologies, the benefits of rotary drilling methods, which produce the cleanest hole and the highest ROPs, and the advantages of steerable drilling techniques, which provide directional flexibility and long horizontal section capabilities, could be achieved.